Question

Which of the following aquated metal ions has the highest paramagnetism?

• A. $\left[Cr\right(H_{2}O{)}_6{]}^{3+}$
• B. $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$
• C. $\left[Cu\right(H_{2}O{)}_6{]}^{2+}$
• D. $\left[Zn\right(H_{2}O{)}_6{]}^{2+}$

Answer 1

The correct option is B $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$

In $\left[Cr\right(H_{2}O{)}_6{]}^{3+}$, the $C{r}^{3+}\left(d^3\right)$ ion outer orbital complex with 3 unpaired electrons

In $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$, the $F{e}^{3+}\left(d^6\right)$ ion outer orbital complex with 4 unpaired electrons

In $\left[Cu\right(H_{2}O{)}_6{]}^{2+}$, the $C{u}^{3+}\left(d^8\right)$ ion contains 1 unpaired electrons

In $\left[Zn\right(H_{2}O{)}_6{]}^{2+}$, the $Z{n}^{2+}\left(d^{1}0\right)$ outer orbital complex with 0 unpaired electrons

Thus highest paramagnetism is exhibited by $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$.